The term “electric vehicle” as used herein, includes vehicles having an electric machine for vehicle propulsion, such as battery electric vehicles (BEV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV). A BEV includes an electric machine, wherein the energy source for the electric machine is a battery that is re-chargeable from an external electric grid. In a BEV, the battery is the source of energy for vehicle propulsion. A HEV includes an internal combustion engine and one or more electric machines, wherein the energy source for the engine is fuel and the energy source for the electric machine is a battery. In a HEV, the engine is the main source of energy for vehicle propulsion with the battery providing supplemental energy for vehicle propulsion (the battery buffers fuel energy and recovers kinematic energy in electric form). A PHEV is like a HEV, but the PHEV has a larger capacity battery that is rechargeable from the external electric grid. In a PHEV, the battery is the main source of energy for vehicle propulsion until the battery depletes to a low energy level, at which time the PHEV operates like a HEV for vehicle propulsion.
Electric vehicles may include a voltage converter (DC-DC converter) connected between the battery and the electric machine. Electric vehicles that have AC electric machines also include an inverter connected between the DC-DC converter and the electric machine. A voltage converter increases (“boosts”) or decreases (“bucks”) the voltage potential to facilitate torque capability optimization. The DC-DC converter includes an inductor (or reactor) assembly, switches and diodes. A typical inductor assembly includes a conductive coil that is wound around a magnetic core. The inductor assembly generates heat as current flows through the coil. An existing method for cooling the DC-DC converter by circulating fluid through a conduit that is proximate to the inductor is disclosed in U.S. 2004/0045749 to Jaura et al.